The invention discloses a method for detecting holdup of split phases in oil sludge based on an induction heating technique and a measuring system. The detection method is based on the formation mechanism and physical-chemical characteristics of the oil sludge, the induction heating technique is adopted, the oil sludge is pyrolyzed according to the set heating curve, and the oil gas and water steam produced by pyrolysis are condensed and collected, and are sent into a metering cylinder; the oil and water in the metering cylinder are naturally separated, the volume of water at the lower layer is read via the scales of the metering cylinder, and the mass of the water is obtained by combining with density; the total mass of oil and water is weighed by an analytical balance, the mass of the water is deducted, and the mass of the oil is obtained; the mass of the oil and the mass of the water are deducted from the mass of the oil sludge, so as to obtain the mass of residue, thereby calculating the holdup of split phases in the oil sludge; by adopting the detection method, the holdup of split phases in the oil sludge can be simultaneously detected, the stored and transported oil sludge can be quickly detected within about one hour, and the detection absolute errors of the three phases are respectively smaller than 2%. The measuring system mainly consists of an induction heating powersupply, an induction heater, a temperature detection module, a controller, a condensing device and a metering test tube.