The utility model provides a power -assisted?steering system and on -vehicle check -out set, through setting up the switching -over valve, a second hydraulic pump and a driving motor, when central controller judges current engine in situ and does not start, start according to a received driving command control driving motor, so that driving motor drive second hydraulic pump, be used for driving the power -assisted?steering motor through the second oil circuit of second hydraulic pump, be in operating condition at on -vehicle check -out set, drive power -assisted?steering system work when the engine in situ does not start, thereby realize not with the help of chassis engine driven power -assisted?steering system, the steering dish is with control traveling direction easily, improve the flexibility and the convenience of the power -assisted?steering system use of on -vehicle check -out set.