The invention relates to a large-channel straight guide type caving-coal transitional hydraulic bracket which comprises upright posts, a top beam and a base, wherein two ends of the top beam are articulated, four upright posts are symmetrically arranged in a form of front and rear rows, a top beam side guard plate is arranged at one side of the top beam, a front beam is articulated at the front end of the top beam, a front beam jack is articulated between the top beam and the front beam, a flexible beam is inserted into the front beam, a flexible beam jack is articulated between a top plate lapped with the front beam and the flexible beam, a tail beam is articulated at the rear end of the top beam, a tail beam side guard plate is arranged at one side of the tail beam, a flashboard is arranged in the tail beam, a flashboard jack is used for pulling and pushing the flashboard, a tail beam jack is articulated between the base and the tail beam, a thrust mechanism, a foot board and a rear-sliding push mechanism are arranged on the base, a straight guide type mechanism is arranged between the base and the top beam between the front and rear rows of upright posts, the straight guide type mechanism comprises a base assembling box body which is integrated with the base and a guide box body corresponding to the base assembling box body, the other end of the guide box body is articulated with the top beam, and a pedestrian passageway is arranged between the straight guide type mechanism and the front row of upright posts.