This paper proposes a multi-step and multi-probe method to measure the roll error of a linear worktable during its movement. Two displacement sensors are used and two measurement steps are employed. Compared with two displacement sensors and a sensing target with high flatness method or a method using autocollimator, this method is in low cost and easier to be carried out. In proposed system, the slope information of roll error is obtained by sensor fusion technology. Roll error estimation algorithm is derived, and sequential-two-point method is used to sample sensors’ signal. Simulation and experimental results show the feasibility of the proposed method.