A construction method of an assembled type pier column member with a steel-concrete composite structure, the method comprising the following steps of: step 1, prefabricating a pile cap, a pier column and a cross beam; wherein the pier column is a hollow steel tube; wherein the cross beam is a steel cross beam with an I-shaped cross section; arranging a stiffening ribbed plate at a lower end of a lower segment of the pier column, arranging a reinforcing mesh clamping sheet inside a tube wall of the lower segment of the pier column at the upper end, and arranging a first flange-plate pier column connecting ring outside an upper end of the tube wall of the lower segment of the pier column; arranging a second flange-plate pier column connecting ring outside an lower end of a tube wall of an upper segment of the pier column, and arranging a T-shaped opening hoop at an upper end of the upper segment of the pier column for lapping I-shaped steel stretched out from the steel cross beam; step 2, embedding a pile cap cross section reinforcement tube in the pile cap for ensuring the installation and positioning of the lower segment of the pier column and reinforcing stress applied to the segment, then pouring the pile cap; step 3, sheathing the lower segment of the pier column on the pile cap cross section reinforcement tube, and pouring concrete to fixedly connect the lower segment of the pier column with the pile cap; step 4, connecting pier columns in upper and lower segments (8, 3) through the first and second flange-plate pier column connecting rings, and arranging reinforcing meshes inside the cross section for reinforcing connection; step 5, connecting the hollow steel tube of the pier column with the steel cross beam, lapping the I-shaped steel stretched out from two ends of the steel cross beam in the T-shaped opening hoop arranged at the upper end of the upper segment of the pier column, and connecting the two in an assembled way through a bolt (13, 15) using a bracket angle steel in the meanwhile; step 6, tensioning a pre-stressed steel strand in a transverse direction of the two ends of the steel cross beam using a post-tensioning method; and step 7, pouring concrete from the steel cross beam into the steel tube and the cross beam step 1, prefabricating a pile cap, a pier column and a cross beam; wherein the pier column is a hollow steel tube; wherein the cross beam is a steel cross beam with an I-shaped cross section; arranging a stiffening ribbed plate at a lower end of a lower segment of the pier column, arranging a reinforcing mesh clamping sheet inside a tube wall of the lower segment of the pier column at the upper end, and arranging a first flange-plate pier column connecting ring outside an upper end of the tube wall of the lower segment of the pier column; arranging a second flange-plate pier column connecting ring outside an lower end of a tube wall of an upper segment of the pier column, and arranging a T-shaped opening hoop at an upper end of the upper segment of the pier column for lapping I-shaped steel stretched out from the steel cross beam; step 2, embedding a pile cap cross section reinforcement tube in the pile cap for ensuring the installation and positioning of the lower segment of the pier column and reinforcing stress applied to the segment, then pouring the pile cap; step 3, sheathing the lower segment of the pier column on the pile cap cross section reinforcement tube, and pouring concrete to fixedly connect the lower segment of the pier column with the pile cap; step 4, connecting pier columns in upper and lower segments (8, 3) through the first and second flange-plate pier column connecting rings, and arranging reinforcing meshes inside the cross section for reinforcing connection; step 5, connecting the hollow steel tube of the pier column with the steel cross beam, lapping the I-shaped steel stretched out from two ends of the steel cross beam in the T-shaped opening hoop arranged at the upper end of the upper segment of the pier column, and connecting the two in an assembled way through a bolt (13, 15) using a bracket angle steel in the meanwhile; step 6, tensioning a pre-stressed steel strand in a transverse direction of the two ends of the steel cross beam using a post-tensioning method; and step 7, pouring concrete from the steel cross beam into the steel tube and the cross beam