A method for acquiring a fingerprint image by a under display optical sensor, comprising: acquiring, before an optical sensor captures a fingerprint image, first optical signals captured by the optical sensor in at least one first region respectively, wherein the first optical signals captured in the at least one first region form a first image, and the at least one first region corresponds to a partial region of a photosensitive surface of the optical sensor, wherein the at least one first region is located at the area where a fingerprint logo for guiding a user to perform pressing is displayed, the first image includes fingerprint information; and identifying whether there is a fingerprint logo in the first image according to the first optical signals captured in the at least one first region; controlling the optical sensor to capture a fingerprint image in the entire area of the photosensitive surface of the optical sensor if there is no fingerprint logo in the first image; wherein the identifying whether there is the fingerprint logo in the first image according to the first optical signals captured in the at least one first region comprises: determining light intensity information of the at least one first region according to the first optical signals captured in the at least one first region; and determining that there is the fingerprint logo in the first image if there is light intensity information greater than a first threshold in the light intensity information of the at least one first region; or determining that there is no fingerprint logo in the first image if there is no light intensity information greater than a first threshold in the light intensity information of the at least one first region; wherein the light intensity information is at least one of optical signal mean, optical signal standard deviation and optical signal variance. acquiring, before an optical sensor captures a fingerprint image, first optical signals captured by the optical sensor in at least one first region respectively, wherein the first optical signals captured in the at least one first region form a first image, and the at least one first region corresponds to a partial region of a photosensitive surface of the optical sensor, wherein the at least one first region is located at the area where a fingerprint logo for guiding a user to perform pressing is displayed, the first image includes fingerprint information; and identifying whether there is a fingerprint logo in the first image according to the first optical signals captured in the at least one first region; controlling the optical sensor to capture a fingerprint image in the entire area of the photosensitive surface of the optical sensor if there is no fingerprint logo in the first image; wherein the identifying whether there is the fingerprint logo in the first image according to the first optical signals captured in the at least one first region comprises: determining light intensity information of the at least one first region according to the first optical signals captured in the at least one first region; and determining that there is the fingerprint logo in the first image if there is light intensity information greater than a first threshold in the light intensity information of the at least one first region; or determining that there is no fingerprint logo in the first image if there is no light intensity information greater than a first threshold in the light intensity information of the at least one first region; wherein the light intensity information is at least one of optical signal mean, optical signal standard deviation and optical signal variance. determining light intensity information of the at least one first region according to the first optical signals captured in the at least one first region; and determining that there is the fingerprint logo in the first image if there is light intensity information greater than a first threshold in the light intensity information of the at least one first region; or determining that there is no fingerprint logo in the first image if there is no light intensity information greater than a first threshold in the light intensity information of the at least one first region; wherein the light intensity information is at least one of optical signal mean, optical signal standard deviation and optical signal variance.