The invention relates to a four-shaft spring connection fixed-weight collision test vehicle, and a test device used for detecting the collision safety of a rail vehicle. The test vehicle comprises a frame and collision wall fixed end assembly body, a weight and fixed guide rail assembly body, a collision wall panel, a spring shaft box and 209P brake disc wheel pair assembly body and a 15# vehiclecoupler assembly body, wherein the weight and fixed guide rail assembly body, the collision wall panel, and the spring shaft box and 209P brake disc wheel pair assembly body are fixed in the inside, the front end and the lower part of the frame and collision wall fixed end assembly body respectively; the front end of the 15# vehicle coupler assembly body is a tested part of the rail vehicle, and the rear end is connected with a power vehicle and serves as a tested part of the rail vehicle; and the spring shaft box and 209P brake disc wheel pair assembly body is adopted for performing a curve test on the four-shaft spring connection fixed-weight collision test vehicle. According to the test vehicle, all test energy can be completely transmitted and applied to the tested parts, and a basis is provided for analyzing the rigidity strength of the rail collision trolley.