An operating method of an optical fingerprint capture apparatus includes: by the apparatus upon receipt of a scan command from a host, entering an exposure mode where an image sensor thereof is exposed to light carrying information of a fingerprint; by the apparatus upon complete exposure of the image sensor to the light, entering a sample mode where multiple pieces of pixel data that cooperatively represent an image of the fingerprint are obtained and written to a data buffer thereof; and by the apparatus at a predetermined output time point that is later than a start of the sample mode and earlier than an end of the sample mode, outputting an interrupt request to cause the host to start reading the pieces of pixel data from the data buffer.