The invention discloses a steel-concrete composite girder construction technology striding over current line and being parallel to existing lines, which comprises the flowing steps: firstly, erecting a supporting falsework, wherein the supporting falsework comprises a plurality of temporary buttresses which are distributed between two buttresses from left to right, and the distribution positions of the plurality of temporary buttresses respectively correspond to the connection position of two adjacent steel grinder sections of a steel grinder body in a construction steel-concrete composite girder; secondly, hoisting the steel grinder sections, wherein a plurality of steel grinder sections constituting the steel grinder body are hoisted in place one by one; thirdly, splicing the steel grinder body, wherein splicing is conducted on the steel grinder body after linetype adjustment and camber adjustment; fourthly, converting the system; fifthly, conducting concrete pouring construction on a ballast channel plate; and sixthly, detaching the supporting falsework. The steel-concrete composite girder construction technology has reasonable design, convenience in the construction, low investment cost, good using effect, high construction efficiency, short construction period and low safety risk, and the adopted supporting falsework has a simple structure and high satiability and is economical and practical.