A scalable architecture for coherent combining of pulsed lasers with active phase control using stochastic parallel gradient descent (SPGD) algorithm is proposed and demonstrated. A low-pass filter is introduced to eliminate the fluctuation of the metric function caused by pulsed lasers and extract the exact phase noise signal, and an active control is thereby built with SPGD algorithm and stable coherent beam combining can be obtained at the receiving plane. Theoretical analysis and numerical simulation were made and an experiment of coherent beam combining two-channel pulsed fiber lasers was also conducted. Experiment results shows that the power encircled in the main-lobe is 1.6 times increased and the fringe visibility of the long exposure pattern is increased from 0 to 0.43 when the system evolves from open-loop to closed-loop. This architecture can be easily scaled up to high power by increasing the number of channel for coherent combining and adding power amplifiers in each channel. 