The disclosure relates to a detection light ranging apparatus and method. The detection light ranging apparatus of the disclosure comprises: a detection light emitting circuit that emits detection light; a first optical assembly that divides the detection light into a first sub-detection light and a second sub-detection light; a second optical assembly that receives the second sub-detection light and causes the second sub-detection light to be emitted after being reflected at least once after being reflected by the measured object; and a timing circuit that receives the first sub-detection light and starts timing to obtain a first time, and receives the second sub-detection light emitted after being reflected at least once and finishes timing to obtain a second time. The detection light ranging apparatus of the disclosure can solve the technical problem of poor measuring precision of the prior ranging apparatuses.