The invention provides a method of using an anti-swelling agent to help a steam flooding in improving the recovery ratio of water-sensitive heavy oil reservoirs. The method comprises the steps of injecting mixed steam and anti-swelling agent solution in a steam injection well of a water-sensitive heavy oil reservoir at the same time and injecting steam in the steam injection well continuously and separately, wherein the anti-swelling agent solution is prepared by diluting a high-concentration mother solution by using preparing water until the concentration is 1% and the mixing ratio of the anti-swelling agent solution to the steam is 1:5. It is needed that the mixed steam and anti-swelling agent solution is injected in the steam injection well continuously for not less than 110 days. The anti-swelling agent is a cationic anti-swelling agent; the injection speed of anti-swelling agent is 1t/h; the injection speed of steam is 5t/h; the degree of dryness of a well bottom must be greater than 40% and the degree of dryness of a well mouth is correspondingly greater than 85%. The effect of heat in the vicinity and prevention in the distance is achieved by using the high temperature steam and the anti-swelling agent, so that the recovery ratio of highly water-sensitive heavy oil reservoirs is improved.