The invention discloses a power failure maintaining device of a hydraulic direction-changing valve. The power failure maintaining device of the hydraulic direction-changing valve comprises a first hinge support, a second hinge support, a position changing lever, a position changing electromagnetic valve, a returning lever and a returning electromagnetic valve, wherein one end of the position changing lever is articulated in the first hinge support; the end of a valve element of the hydraulic direction-changing valve abuts against the side of the position changing lever; a lock pin is convexly arranged on the position changing lever; the end of a valve element of the position changing electromagnetic valve is articulated with the other end of the position changing lever; the position changing electromagnetic valve is used for driving the position changing lever to swing; one end of the returning lever is articulated in the second hinge support; a lock card is convexly arranged at the other end of the returning lever; the lock pin on the position changing lever abuts against the bottom end of a slope of the lock card of the returning lever in an initial state; the end of a valve element of the returning electromagnetic valve is articulated with the middle part of the returning lever; the returning electromagnetic valve is used for driving the returning lever to swing. According to the power failure maintaining device of the hydraulic direction-changing valve, the lock pin of the position changing lever cooperates with the lock card of the returning lever to implement the power failure maintaining function of the hydraulic direction-changing valve; the power failure maintaining device is simple in structure and easy to implement, and achieves power economization and energy economization.