Due to the Von Neumann bottleneck, in-memory-computing, as a new architecture, has drawn considerable attention and is becoming an candidate of next generation electronics system. It presents an inmemory-computing approach for multiplier design based on Multilevel-cell (MLC) of Resistive random access memories (RRAMs). The paper proposes a Look-up-table (LUT) operations to optimize the speed, area and power of the multiplier circuits. The proposed MLC function of RRAM revealed that RRAM could have a multilevel stable resistance by adjusting the operating voltage. The simulation results show that, taking a 16-bits multiplier as an example, the circuits of this paper has a calculation speed thatis increased by 35.7 percent and an area that is decreased by 14 percent under the similar power consumption conditions when compared with other traditional 16-bits multiplier.