A LED mounting base, comprising a block base and supporting means, wherein a front end surface of the supporting means is suitable for being used as for mounting a LED chip, the LED chip is used for red dot sight, wherein the supporting means is disposed on a front end surface of the block base, wherein a position locking mechanism in the form of a sliding slot is disposed on the front end surface of the block base and parallel to a length direction of the block base, wherein after the supporting means being disposed in the sliding slot, the front end surface of the supporting means is flush with the front end surface of the block base; wherein the supporting means is configured to reciprocate along the length direction of the block base through the position locking mechanism; wherein at least two blind holes uniformly disposed along a length direction of the sliding slot are disposed on an inner end surface of the sliding slot, a first contact-press structure being mounted in the blind hole, wherein the first contact-press structure comprises a spiral spring, a hollow clamping cap and a steel ball with a diameter larger than an inner diameter of a front end outlet of the hollow clamping cap, all of which are sequentially mounted in the blind hole from an inside to an outside; under the action of the spiral spring, the steel ball is touched against the front end outlet of the hollow clamping cap after entering the hollow clamping cap from a back end of the hollow clamping cap, and a part of a spherical surface of the steel ball is exposed at an outside of the front end outlet of the hollow clamping cap to contact against the back end surface of the supporting means; wherein a top surface of the supporting means is provided with at least two uniformly distributed grooves along a length direction of the supporting means, a second contact-press structure with the same structure as the first contact-press structure being mounted in the groove for pressing against an inner top surface of the sliding slot opposite to the top surface of the supporting means. wherein after the supporting means being disposed in the sliding slot, the front end surface of the supporting means is flush with the front end surface of the block base; wherein the supporting means is configured to reciprocate along the length direction of the block base through the position locking mechanism; wherein at least two blind holes uniformly disposed along a length direction of the sliding slot are disposed on an inner end surface of the sliding slot, a first contact-press structure being mounted in the blind hole, wherein the first contact-press structure comprises a spiral spring, a hollow clamping cap and a steel ball with a diameter larger than an inner diameter of a front end outlet of the hollow clamping cap, all of which are sequentially mounted in the blind hole from an inside to an outside; under the action of the spiral spring, the steel ball is touched against the front end outlet of the hollow clamping cap after entering the hollow clamping cap from a back end of the hollow clamping cap, and a part of a spherical surface of the steel ball is exposed at an outside of the front end outlet of the hollow clamping cap to contact against the back end surface of the supporting means; wherein a top surface of the supporting means is provided with at least two uniformly distributed grooves along a length direction of the supporting means, a second contact-press structure with the same structure as the first contact-press structure being mounted in the groove for pressing against an inner top surface of the sliding slot opposite to the top surface of the supporting means.