The invention discloses a provincial grid regional mutual aid contribution level evaluation method for coping with power deficiency. The method comprises the following steps: 1) dividing the grids participating in regional mutual aid into trans-regional tie line support grids and trans-provincial tie line support grids; 2) performing optimized assessment on the provincial grid regional mutual aidsupport capability according to the load level, backup capacity, power structure and grid structure of the trans-provincial tie line support grids; 3) calculating a support indicator and a contribution indicator of the provincial grid regional mutual aid; 4) establishing a regional mutual aid contribution level comprehensive evaluation indicator model based on a nonlinear exponential function; and5) calculating a provincial grid regional mutual aid contribution level evaluation result for coping with high power deficiency. The method is beneficial to sufficiently motivating regional mutual aid of provincial grids, and improves the safety operating level of a large grid coping with the power deficiency.