Fixing support of mechanical jack of automobile and fixing method of jack

The invention relates to a fixing support of a mechanical jack of an automobile. The fixing support of the mechanical jack of the automobile is characterized by comprising a tension brace (21), a first supporting body (28) and a second supporting body (29), wherein the first supporting body (28) and the second supporting body (29) are symmetrically arranged at two ends of the tension brace (21). Limiting baffles (23) are respectively symmetrically arranged on the front sides and the rear sides of both a first supporting body supporting surface (22) of the first supporting body (28) and a second supporting body supporting surface (26) of the second supporting body (29). The fixing support of the jack further comprises a limiting rod and an adjusting device, one end of the limiting rod is fixed with a rear side vertical plate (27) of the tension brace (21) after penetrating through a jack recession (14), and the other end of the limiting rod and the adjusting device are matched with each other to jointly abut a