Intense, femtosecond X-ray pulses from X-ray free electron laser （XFEL） have enabled acquisition of diffraction patterns from protein microcrystals before the onset of radiation damage. Although a single-shot exposure of XFEL destroys a crystal, diffraction by XFEL terminates before movements of atoms become significant. Thus, XFEL allows determination of damage free structures at room temperature. In serial femtosecond crystallography, fresh microcrystals are continuously delivered by an injector to the XFEL interaction zone. When combined with an excitation laser in a pump-probe setting, this technique is of great utility for time-resolved experiments in measuring ultra-fast reactions in proteins. We will describe current situation of SFX experiments at SACLA and future prospects.