The optimal strategies of in plane maneuver avoidance are proposed for the dangerous assessment of two spacecrafts. The strategies can calculate the optimal impulsive with reduce collision probability and increase miss distance. Firstly, Closed form analytical expressions with the maneuvering impulsive and spacecraft relative motion are obtained by combining the Gaussian perturbation equation and Taylor expansion in the encounter bplane. Then, the expressions of collision probability and miss distance are obtained by the relative position covariance information and the relative position information of the two spacecrafts, and collision avoidance impulsive is calculated by a two steps strategy. Finally, some mathematical simulations for the proposed strategies are implemented. The simulation results indicate that using the proposed maneuver strategies, we can get the optimal impulsive.