The invention discloses a dual-oil way hydraulic gap adjuster for driving working condition conversion of a valve rocker. The dual-oil way hydraulic gap adjuster comprises a shell, a ball head plunger and a check valve mechanism, wherein the ball head plunger and the check valve mechanism are assembled in the shell; the upper part of the ball head plunger is a ball head; an oil outlet is formed in the top of the ball head; oil inlets and oil charging holes are formed in the shell; a gap adjustment plunger is arranged between the ball head plunger and the check valve mechanism; oil inlets are formed in the ball head plunger; oil charging holes are formed in the gap adjustment plunger; and the oil inlets and the oil charging holes of the two kinds are communicated through the gaps of the mechanism. According to the invention, the mechanism is simple and reliable, is compact in assembly, and quite convenient to process; the two functions that the gaps between a cam and the rocker are adjusted, and the working conditions of the rocker are changed through providing engine oil with different pressure for the rocker are achieved at the same time; the space inside a cylinder cover is saved; the ball head plunger is formed through directly stamping a iron sheet, and adopts a hollow chamber inside, so that the weight is light; a plurality of the oil inlets are formed, so that compared with a solid plunger with only two oilholes, the ball head plunger has the advantages of high oil inlet efficiency and quick response during oil pressure switch.