A height measuring apparatus and a method thereof are disclosed. The disclosed method is suitable for an indoor environment. The disclosed method comprises emitting a first laser to a ceil via a first light path, determining whether a first reflective light corresponding to the first laser is received, emitting a second laser to an object via a second light path reflected by the ceil, determining whether a second reflective light corresponding to the second laser is received, calculating a first length according to a first data corresponding to the first reflective light, calculating a second length according to a second data corresponding to the second reflective light, and calculating an object height of the object according to the first length and the second length.