A work machine hydraulic control system comprising: a hydraulic pump (17; 17A); a hydraulic apparatus connected to a delivery side of the hydraulic pump (17; 17A); a pump output power switching device (27; 36) selectively switching the hydraulic pump (17; 17A) between a high output power and a low output power; an accumulator connected to a hydraulic line between the hydraulic pump (17; 17A) and the hydraulic apparatus, accumulating a portion of a hydraulic fluid delivered from the hydraulic pump (17; 17A) when the hydraulic pump (17; 17A) is of high output power, and supplying the hydraulic fluid to the hydraulic apparatus when the hydraulic pump (17; 17A) is of low output power; a pump check valve permitting flow of the hydraulic fluid from the hydraulic pump (17; 17A) to the hydraulic apparatus and the accumulator and preventing flow of the hydraulic fluid from the accumulator to the hydraulic pump (17; 17A); a pressure sensor detecting a pressure of the hydraulic fluid supplied to the hydraulic apparatus from one of the hydraulic pump (17; 17A) and the accumulator; and a controller (30; 30A; 30B) having a pump output power control section (31; 31A) that in a case where a pressure value of the pressure sensor is equal to or more than a previously set upper limit value when the hydraulic pump (17; 17A) is of high output power, outputs a low output power command to the pump output power switching device (27; 36) in order to switch the hydraulic pump (17; 17A) to low output power, and that in a case where the pressure value of the pressure sensor is equal to or less than a previously set lower limit value when the hydraulic pump (17; 17A) is of low output power, outputs a high output power command to the pump output power switching device (27; 36) in order to switch the hydraulic pump (17; 17A) to high output power, characterized in that the controller (30; 30A; 30B) further comprises an abnormality determination section (32; 32A; 32B) that computes a command continuation time in a state in which the command output from the pump output power control section (31; 31A) to the pump output power switching device (27; 36) is not changed, and that in a case where the command continuation time is equal to or more than a previously set predetermined value, determines that there is abnormality in the pump output power switching device (27; 36), and outputs a determination result. a hydraulic pump (17; 17A); a hydraulic apparatus connected to a delivery side of the hydraulic pump (17; 17A); a pump output power switching device (27; 36) selectively switching the hydraulic pump (17; 17A) between a high output power and a low output power; an accumulator connected to a hydraulic line between the hydraulic pump (17; 17A) and the hydraulic apparatus, accumulating a portion of a hydraulic fluid delivered from the hydraulic pump (17; 17A) when the hydraulic pump (17; 17A) is of high output power, and supplying the hydraulic fluid to the hydraulic apparatus when the hydraulic pump (17; 17A) is of low output power; a pump check valve permitting flow of the hydraulic fluid from the hydraulic pump (17; 17A) to the hydraulic apparatus and the accumulator and preventing flow of the hydraulic fluid from the accumulator to the hydraulic pump (17; 17A); a pressure sensor detecting a pressure of the hydraulic fluid supplied to the hydraulic apparatus from one of the hydraulic pump (17; 17A) and the accumulator; and a controller (30; 30A; 30B) having a pump output power control section (31; 31A) that in a case where a pressure value of the pressure sensor is equal to or more than a previously set upper limit value when the hydraulic pump (17; 17A) is of high output power, outputs a low output power command to the pump output power switching device (27; 36) in order to switch the hydraulic pump (17; 17A) to low output power, and that in a case where the pressure value of the pressure sensor is equal to or less than a previously set lower limit value when the hydraulic pump (17; 17A) is of low output power, outputs a high output power command to the pump output power switching device (27; 36) in order to switch the hydraulic pump (17; 17A) to high output power, characterized in that the controller (30; 30A; 30B) further comprises an abnormality determination section (32; 32A; 32B) that computes a command continuation time in a state in which the command output from the pump output power control section (31; 31A) to the pump output power switching device (27; 36) is not changed, and that in a case where the command continuation time is equal to or more than a previously set predetermined value, determines that there is abnormality in the pump output power switching device (27; 36), and outputs a determination result.