Laser reflection measurement on liquid lithium flow surface

•We have been studying a liquid lithium surface wave fluctuation for IFMIF.•We developed a new method using laser to measure the lithium surface.•The result from the laser method was compared with the result of previous study using contact probe method.•The result from the laser method was obtained a new phenomenon that was not measure by the probe method.•Proof of principle experiment of laser method was performed successfully.