Grid-forming inverter has strong applicability for weak grid, but it has transient stability problem under large power scheduling step. Firstly, the static stability limit power and power angle of the grid-forming inverter is analyzed in this paper. Based on the equal area criterion, the influence of power climbing step size on transient stability is analyzed. Two types of improved active power climbing control strategies for power scheduling are proposed with the constraint of transient stability. Finally, the simulation results verify the feasibility and validity of the above analysis.