The invention provides a portable automobile gearshift system measuring instrument. The instrument comprises a clamp for clamping a gearshift knob, a universal joint is arranged above the clamp, a two-dimensional force transducer is connected above the universal joint, the side surface of the universal joint is connected with a displacement sensor, and the displacement sensor and an angular sensor are fixed together and are arranged on a vehicular-mounted support. The invention also provides a portable automobile gearshift system measuring method. Through gear demonstration, distribution of gear points of a gearshift device is identified by use of a spherical coordinate measuring system, obtained parameters are converted into three-dimensional right-angle work coordinate system parameters in real time, and at the same time, performing projection to obtain a two-dimensional plane curve; and according to repeatability of gearshift paths in multiple measuring processes, displacement variation scope of the gear points under specific gearshift forces and the size of the gearshift forces, evaluating the performance of a gearshift system. According to the invention, the automatic gearshift system can be automatically measured, the knob does not have to be dismounted during testing, the application is convenient, the test result is accurate, and the portable automobile gearshift system measuring instrument and method can be applied to quantitative evaluation of the automatic gearshift system.