The invention discloses a testing machine and testing method for low-temperature contraction performance of rubber. The testing machine is reasonable in structural design and is fully automatic in operation, and comprises a case body and a frame located on the case body, wherein the frame is connected with a supporting plate, a clamping mechanism is arranged on the supporting plate, a sensing mechanism is arranged on the clamping mechanism, the clamping mechanism comprises a clamp group, a driving belt, a pulley and a weight, the clamp group comprises an upper clamp and a lower clamp, the sensing mechanism comprises a magnetic grid ruler and a magnetic grid ruler reading head arranged on the driving belt, a refrigeration system is arranged in the case body, and the testing machine is connected with a computer software control system. According to the invention, the testing machine is convenient for operation and high in working efficiency, and can simultaneously test multiple groups of samples; and the testing method is easy to operate, realizes the testing of the low temperature contraction performance of rubber, improves the testing precision, and provides guarantee for the mass production and use as well as performance improvement of the rubber.