A sense amplifier (SA), a memory and a control method are provided. The SA includes an amplifying module, configured to amplify voltage difference between a BL and a BLB when the SA is in an amplifying stage; a controllable power module, connected to the amplifying module and configured to stop providing power to the amplifying module when the SA is in a writing stage, to enable the amplifying module to stop working; and a writing module, connected to the BL and the BLB and configured to pull the voltage difference between the BL and the BLB according to data to be written when the SA is in the writing stage. The solution may ensure the successful data writing in a storage unit in a case that a writing circuit has weak drive capability.