A control valve comprising an oil circuit provided between a first port G and a second port F, and an oil circuit provided between a third port H and a fourth port E; wherein a first balance valve connected in series with a switch valve is provided in the oil circuit between the first port G and the second port F; wherein a second balance valve is provided on the oil circuit between the third port H and the fourth port E; wherein the first balance valve, the second balance valve, and the switch valve are integrated in one valve body, the first port G, the second port F, the third port H and the fourth port E are located on a surface of the valve body; wherein the first balance valve comprises a first one-way functional portion and a first overflow function portion, and the second balance valve comprises a second one-way functional portion and a second overflow function portion; the control port of the first overflow function portion is in communication with a first oil mouth located at one end of the oil inlet of the second one-way function portion of the second balance valve; and the control port of the second overflow function portion is in communication with a second oil mouth located at one end of the oil inlet of the first one-way function portion of the first balance valve; and a third oil mouth located at one end of the oil inlet of the first overflow function portion of the first balance valve is connected to the second port F; and the second oil mouth is connected to the first port G, the first oil mouth is connected to the third port H; and a fourth oil mouth located at one end of the oil inlet of the second overflow function portion of the second balance valve is connected to the fourth port E; wherein the switch valve is provided on an oil circuit between the first port G and the first balance valve, and characterized in that the control valve further comprises a hydraulic sensor configured to monitor the pressure on the oil circuit between the switch valve and the first balance valve; an electronic control unit electrically connected to the hydraulic sensor; and an alarm device electrically connected to the electronic control unit. wherein a second balance valve is provided on the oil circuit between the third port H and the fourth port E; wherein the first balance valve, the second balance valve, and the switch valve are integrated in one valve body, the first port G, the second port F, the third port H and the fourth port E are located on a surface of the valve body; wherein the first balance valve comprises a first one-way functional portion and a first overflow function portion, and the second balance valve comprises a second one-way functional portion and a second overflow function portion; the control port of the first overflow function portion is in communication with a first oil mouth located at one end of the oil inlet of the second one-way function portion of the second balance valve; and the control port of the second overflow function portion is in communication with a second oil mouth located at one end of the oil inlet of the first one-way function portion of the first balance valve; and a third oil mouth located at one end of the oil inlet of the first overflow function portion of the first balance valve is connected to the second port F; and the second oil mouth is connected to the first port G, the first oil mouth is connected to the third port H; and a fourth oil mouth located at one end of the oil inlet of the second overflow function portion of the second balance valve is connected to the fourth port E; wherein the switch valve is provided on an oil circuit between the first port G and the first balance valve, and characterized in that the control valve further comprises a hydraulic sensor configured to monitor the pressure on the oil circuit between the switch valve and the first balance valve; an electronic control unit electrically connected to the hydraulic sensor; and an alarm device electrically connected to the electronic control unit.