Vehicle mass and road slope are important parameters of active safety control system. This paper presents a serial estimation algorithm for vehicle mass and road slope. The vehicle mass and road slope are estimated in a hierarchical and serial manner according to changing speed. The slowly varying vehicle mass is taken as the estimated output of the first layer， and the rapidly varying road slope is taken as the estimated output of the second layer. The estimation algorithm is based on longitudinal dynamics. Firstly， the vehicle mass of the first layer is estimated through recursive least squares （RLS） algorithm based on tire driving moment and angular velocity， and then the estimated vehicle mass is substituted into the second-layer Newton iteration method for road slope estimation. Compared with the traditional adaptive estimation method， the proposed algorithm can reduce the coupling effect of real-time estimation parameters and does not require additional sensors. Finally， the algorithm is verified through simulation and electric control model vehicle road test， and the simulation and test results show that the proposed identification algorithm can accurately estimate vehicle mass and road slope in a real-time manner.