The invention provides an elastic connecting seat for connecting a carriage and an auxiliary frame. The elastic connecting seat comprises a sleeve, a carriage support platform connected with the top of the carriage, a bolt, a nut and a spring, wherein a sleeve fixing plate connected with the auxiliary frame is arranged on the upper end face of the sleeve; an axle hole coaxial with the sleeve is formed on the carriage support platform; the bolt passes through the spring, the sleeve and the carriage support platform in sequence, and is locked through the nut; and the carriage support platform is sleeved at the opening at the upper end of the sleeve. Therefore, after the carriage and the auxiliary frame are connected by the elastic connecting seat, destruction of inertia force can be eliminated to ensure driving safety.