A read-write control circuit is used for preventing a CPU (central processing unit) from changing parameters of a digital integrated chip through a system management bus when the CPU is inserted into a CPU slot. The CPU slot comprises a presence signal pin. The read-write control circuit comprises a PMOS (P-channel metal oxide semiconductor) transistor, an NMOS (N-channel metal oxide semiconductor) transistor, a first power supply, a second power supply, a first resistor, a second resistor and a third resistor. One end of the first resistor is connected with a first power supply, and the other end of the first resistor is grounded through the second resistor. The presence signal pin of the CPU slot and a gate of the NMOS transistor are both connected to a node between the first resistor and the second resistor, a source of the NMOS transistor is grounded, and a drain of the NMOS transistor is connected to the second power supply through the third resistor. One end of a fourth resistor is connected with the drain of the NMOS transistor, and the other end of the fourth resistor is connected with a gate of the PMOS transistor. A drain of the PMOS transistor is connected with the digital integrated chip, and a source of the PMOS transistor is connected with a data transmission line of the system management bus. By the read-write control circuit, the digital integrated chip damage caused by false change of parameters of the digital integrated chip can be avoided.