The invention provides a physical simulation experimental device and method for water invasion and drainage gas recovery in gas reservoir, and the experimental device includes: a heterogeneous reservoir model having a first core holder, a second core holder, a third core holder and a fourth core holder, wherein the third core holder is connected between the first core holder and the second core holder, and the fourth core holder is connected between an outlet end of the first core holder and an outlet end of the second core holder; a gas injection mechanism having a gas injection bottle and a gas injection cylinder; a water body simulation mechanism having a water storage tank and a water injection pump. The invention can simulate and reveal different drainage gas recovery modes, timings, scales and their influences on the recovery ratio of the gas reservoir.