As long as there is economic activity, there should be an act of signing an economic contract. The economic activity of the "Qian Qishun" is actually a "immediate contract", that is, the economic contract that was settled at that time. The situation in which economic activity is generated without a contract usually occurs between an acquaintance, a colleague, a relative, and a friend. In this case, more and more in the project of the construction enterprise, it is generally conducted in the project sub-contract, equipment lease and labor service without signing an economic contract or an ex post-payment contract.