A light emitting diode bulb which has an axis and comprises: a lamp housing comprising: a first adjusting member, comprising: at least one first engaging structure; a first acting surface; and a second acting surface, wherein the first acting surface and second acting surface are respectively located on an upside and an underside of the first engaging structure; and a second adjusting member, which can be moved along the axis in relation to the first adjusting member and be fixed at a first position or a second position, wherein the second adjusting member comprises at least one second engaging structure corresponding to the at least one first engaging structure, and the second engaging structure comprises: an upper opposing surface, wherein when the second adjusting member is fixed at the first position, the upper opposing surface is against the second acting surface; and a lower opposing surface, wherein when the second adjusting member is fixed at the second position, the lower opposing surface is against the first acting surface; a light source module which is disposed on the second adjusting member and is moved along the axis with the second adjusting member; a lampshade which is disposed on a top end of the lamp housing and covers the light source module; and a lamp cap disposed on a bottom end of the lamp housing characterized in that the light source module further comprises: a base fixed on the second adjusting member, wherein the base has a flange, when the second adjusting member is fixed at the first position, the flange is against the first acting surface, and at least one light emitting diode module disposed on the base. a lamp housing comprising: a first adjusting member, comprising: at least one first engaging structure; a first acting surface; and a second acting surface, wherein the first acting surface and second acting surface are respectively located on an upside and an underside of the first engaging structure; and a second adjusting member, which can be moved along the axis in relation to the first adjusting member and be fixed at a first position or a second position, wherein the second adjusting member comprises at least one second engaging structure corresponding to the at least one first engaging structure, and the second engaging structure comprises: an upper opposing surface, wherein when the second adjusting member is fixed at the first position, the upper opposing surface is against the second acting surface; and a lower opposing surface, wherein when the second adjusting member is fixed at the second position, the lower opposing surface is against the first acting surface; a first adjusting member, comprising: at least one first engaging structure; a first acting surface; and a second acting surface, wherein the first acting surface and second acting surface are respectively located on an upside and an underside of the first engaging structure; and at least one first engaging structure; a first acting surface; and a second acting surface, wherein the first acting surface and second acting surface are respectively located on an upside and an underside of the first engaging structure; and a second adjusting member, which can be moved along the axis in relation to the first adjusting member and be fixed at a first position or a second position, wherein the second adjusting member comprises at least one second engaging structure corresponding to the at least one first engaging structure, and the second engaging structure comprises: an upper opposing surface, wherein when the second adjusting member is fixed at the first position, the upper opposing surface is against the second acting surface; and a lower opposing surface, wherein when the second adjusting member is fixed at the second position, the lower opposing surface is against the first acting surface; an upper opposing surface, wherein when the second adjusting member is fixed at the first position, the upper opposing surface is against the second acting surface; and a lower opposing surface, wherein when the second adjusting member is fixed at the second position, the lower opposing surface is against the first acting surface; a light source module which is disposed on the second adjusting member and is moved along the axis with the second adjusting member; a lampshade which is disposed on a top end of the lamp housing and covers the light source module; and a lamp cap disposed on a bottom end of the lamp housing characterized in that the light source module further comprises: a base fixed on the second adjusting member, wherein the base has a flange, when the second adjusting member is fixed at the first position, the flange is against the first acting surface, and at least one light emitting diode module disposed on the base. a base fixed on the second adjusting member, wherein the base has a flange, when the second adjusting member is fixed at the first position, the flange is against the first acting surface, and at least one light emitting diode module disposed on the base.