How do you judge whether a Chihuahua is pure or not? It is best for a Chihuahua to have a round "apple-shaped" head, a slightly curved neck, a horizontal topline, a moderately long tail, narrow forelimbs and shoulders that gradually widen downwards, and straight front legs. Allows unrestricted elbow movement, strong hind limb muscles, and appropriate distance; the coat of the Chihuahua short-haired type is very soft, tight and smooth.

Chihuahua’s head is preferably a round “apple-shaped” head. Beautiful expression. The eyes are large but not protruding, well-proportioned, and preferably bright black or red (white eyes are allowed for yellowish or white dogs). The ears are large and erect, and remain more erect when alert, but when at rest, the ears are separated and the two ears are at a 45-degree angle. The muzzle is short and slightly pointed. Black, blue and chocolate varieties have nose colors consistent with their body color. Pink noses are allowed in yellowish varieties. Scissor or pincer bite. An overgnath or undergnath is a serious fault. Ear cropping will result in disqualification.

The neck of the Chihuahua’s torso is slightly curved, perfectly integrating with the shoulders. Topline level. The rounded ribs support the chest and make the body strong and strong (but not barrel chest). The tail is of moderate length, held high or outward in a sickle shape, or rolled over the back, with the tip of the tail just touching the back (never sandwiched between the legs). Short or docked tails are a disqualification.

The Chihuahua’s forelimbs have narrow shoulders and gradually widen downwards. The front legs are straight, allowing unrestricted elbow movement. The shoulders should be up, balanced and strong, sloping toward the back (the shoulders should not be down or too low). Broad chest and strong forequarters, but never "bulldog" chest. The feet are slender, the toes are spaced just right apart on the beautiful little feet, but not too far apart, and the pads are thick (not like rabbit or cat feet). The ankles are slender. The hindquarters are well muscled, well spaced, neither too far in nor too far out, looking downward, strong and solid. The feet are the same as the forelimbs.

The coat texture of the Chihuahua short-haired type is very soft, tight and smooth (undercoat is allowed when the hair volume is large enough). The coat covers the dog's body and has a fur collar and tail, and the hair is sparse on the head and ears. The hair on the tail resembles fur. The long-haired coat is soft, flat or slightly curved, preferably with an undercoat. The edges of the ears are feathered (if the ears are thin and have more feathers, the ears may tilt forward slightly, but never downward). The tail is plump and long (feathery). Ideally: fur on the feet and legs, shorts on the back, and a fur collar on the neck. Long-haired type is disqualified: the coat is sparse and nearly naked.

Chihuahuas should preferably weigh no more than 6 pounds. The proportions of the body are rectangular; so the length from shoulder to hip is slightly greater than the height at the withers. A slightly shorter body for males is ideal. Any weight over 6 pounds is disqualifying.

Chihuahuas move quickly and firmly, with strong hindquarter driving force. Viewed from behind, the hind legs should always be parallel to each other and the foot of the hind foot should always follow the front foot. Both the front and rear legs tend to move slightly toward the center line of gravity to increase speed. Viewed from the side, the forequarters guide and the hindquarters driveMove, hold your head high. During action, the topline remains level and stable. Elegant and effortless, with long, strong forelegs and strong propulsion in the hindquarters. When viewed from the side, the stride length is appropriate, and when viewed from the front and back, the walking pattern is straight. This is due to sound bones and muscles.