Disclosed are a current sampling apparatus and a current sampling method for an isolated power converter. The isolated power converter includes a square wave generator, an isolated transformer, and a primary side filter circuit coupled therebetween. The current sampling apparatus includes: a first sampling circuit coupled to the primary side of the isolated transformer and sampling a total current of the primary side of the isolated transformer and outputting a first sampling current; and a shunt circuit receiving the first sampling current. The shunt circuit includes a first shunt branch circuit through which the first sampling current is transformed into an excitation sampling current and a second shunt branch circuit through which the first sampling current is transformed into a current to be sampled.