The invention discloses a tubing head blocking isolating valve for a fracture wellhead device. The tubing head blocking isolating valve comprises a tubing head four-way piece. Two valve seats which are symmetrical left and right are assembled in a horizontal channel of an inner cavity of the tubing head four-way piece. A valve plate is arranged between the two valve seats in a sleeving mode, the lower end of the valve plate is connected with a tail rod, and the upper end of the valve plate is connected with a valve rod. The valve rod extends upwards to be exposed out of a shell of the tubing head four-way piece and connected with a valve rod nut in a threaded and sleeved mode, and a hand wheel is fixedly connected to the upper end face of the valve rod nut. One end of the tubing head four-way piece is connected with a fracture tree and provided with two side connectors, and the other end of the tubing head four-way piece is connected with a wellhole. According to the tubing head blocking isolating valve, lots of water resources are saved, the wellhole can be effectively protected, the safety coefficient of the wellhole is increased, and the safety of a wellhead is greatly guaranteed because rated working pressure testing can be performed on the fracture wellhead device.