At present

4G is in the ascendant

and 5G has arrived. During the coexistence of two networks

we should not only make use of the existing advantages of 4G network

but also give full play to the new capabilities of 5G network

so that two networks can play a greater joint force and create more value. Firstly

this paper studies the cooperative scheme of 5G + 4G network construction

and then puts forward the cooperative strategy of 5G + 4G network in the early stage of NSA.