Memory, operation method thereof, and memory system

A memory system, comprising:

• one or more memory, comprising:
• a memory array comprising a plurality of memory cells;
• and
• a peripheral circuit coupled with the memory array and configured to:
• apply N program voltages to a word line coupled with a to-be-programmed memory cell with a target state to perform a first program operation, to program the to-be-programmed memory cell to a first threshold voltage without programming other to-be-programmed memory cells to a first threshold voltage, wherein the target state comprises a highest target state from among multiple target states, wherein a difference between a target threshold voltage corresponding to the to-be-programmed memory cell with the target state and the first threshold voltage is less than a first preset value, and N is a positive integer;
• and
• apply M program voltages to the word line to perform a second program operation, to program both the to-be-programmed memory cell with the target state and other to-be-programmed memory cells that are coupled with the word line to respective corresponding target threshold voltages, wherein M is a positive integer;
• and
• a memory controller, coupled with the memory and controlling the memory.