The invention discloses a combinable trolley. The combinable trolley comprises at least two combination trolley bodies (1). Every two adjacent combination trolley bodies (1) are connected through a fixing support (2). Each combination trolley body (1) comprises a trolley main frame (11), a trolley top mold (12), a side mold (13), a haunch formwork (14) and a trolley base (15). Each fixing support (2) comprises a support main frame (21) and a support top mold (22). The construction method of the combinable trolley includes the following steps: positioning an upper construction face, positioning the haunch formworks, positioning the side molds, carrying out construction, releasing the side molds, releasing the haunch formworks, releasing the top molds, advancing the trolley and beginning a next work cycle. By means of the combinable trolley and the construction method, the aim that side walls and floors are constructed at the same time is achieved, and the requirements for constructing different cross section types and different widths in a station are further met. By means of the trolley, the combination way is versatile, free combining can be achieved, and independent work can also be achieved.