The productive forces theory is an important part of Capital.In Capital and its manuscripts,Marx systematically explained the connotation,characteristics and movement laws of the productive forces,clearly put forward the conclusion that"science has become a direct productive force",profoundly revealed the possession,development and restriction of the productive forces by capital under the capitalist mode of production,and scientifically pointed out the realistic road to liberate and develop the productive forces.Xi Jingping's important discussion on the development of the new quality productive forces is the inheritance and development of the productive forces theory in Capital,and has made an original contribution to the Marxist productive forces theory.