The method relates to a method for testing early capillary negative pressure of concrete, which uses an automatic testing device for the early capillary negative pressure of the concrete. The automatic testing device for the capillary negative pressure consists of a pressure sensor, a ceramic head, a gas collecting pipe, a pipe plug, a measuring cylinder, a needle, a transmitter, an A/D converter and a computer; wherein the ceramic head is arranged at the bottom part of the gas collecting pipe, the pipe plug is arranged at the top part of the gas collecting pipe, micro-pores are formed on the surface and in the interior of the ceramic head, the pore diameter of the micro-pores is 0.01-0.035 Mum, the pressure sensor is arranged in the measuring cylinder, and the needle arranged at the front end of the measuring cylinder penetrates the pipe plug to extend into the gas collecting pipe; data measured by the pressure sensor is sent to the A/D converter by the transmitter and sent to the computer for analysis and treatment after the analog/digital conversion. The method is based on thermodynamics and surface physical chemistry and starts from the definition of self-desiccation shrinkage, thereby realizing the quantitative automatic research of earliest water consumption laws of cement-based materials and having simple and easy operation.