The invention discloses an optimization method for highway horizontal curve radius safety design based on a vehicle side-turn and side-slip virtual test. The method comprises the steps that 1, an optimization objective function Q(r) is established; 2, a driver-vehicle-target section virtual test simulation platform is constructed; 3, dynamic indicators of a vehicle running at a design speed are acquired, and values of the lateral acceleration rate LTA and the load transfer rate LTR are calculated; 4, if LTA is smaller than or equal to 0.9 and LTR is smaller than or equal to 0.9, the value of Q(r) is calculated, and the step 6 is skipped to; if LTA is not smaller than or equal to 0.9 and LTR is not smaller than or equal to 0.9, the step 5 is skipped to; 5, the highway horizontal curve radius r is increased by delta r, and the steps 2, 3 and 4 are repeated; 6, the line segment length l between the current radius and a horizontal curve adjacent to an optimal objective horizontal curve is calculated; if r is greater than or equal to r or l is smaller than or equal to l, the step 7 is skipped to; if r is not greater than or equal to r or l is not smaller than or equal to l, r is increased by delta r, and the steps 2, 3 and 4 are repeated; 7, different r-value virtual test simulation results are compared, and the r enabling the Q(r) value to be minimum is selected to serve as the optimal design scheme. The optimization method is rapid and effective for safety of horizontal curve radius design schemes of a highway at all stages.