A method for detecting ambient light, comprising: determining, by mobile User Equipment, UE, comprising a display and a light sensor, a first brightness value and a second brightness value, the first brightness value being acquired by the light sensor in a display state of the display during a display time window, the second brightness value being acquired by the light sensor in an off state of the display during an off time window, wherein the display is off during the off time window; determining a first drop depth value according to the first brightness value and the second brightness value; and acquiring a second ambient brightness value by adjusting a first ambient brightness value detected by the light sensor based on a brightness adjusting model acquired under predetermined ambient light and the first drop depth value, characterized in that the brightness adjusting model is acquired under the predetermined ambient light by: determining, under the predetermined ambient light, a third brightness value and a fourth brightness value, the third brightness value being acquired by the light sensor in the display state of the display during the display time window, the fourth brightness value being acquired by the light sensor in the off state of the display during the off time window; determining a second drop depth value according to the third brightness value and the fourth brightness value; and determining the brightness adjusting model for adjusting the first ambient brightness value by performing values fitting according to the second drop depth value and a third ambient brightness value under the predetermined ambient light, wherein the third ambient brightness value is determined according to known brightness of the predetermined ambient light, and is adapted to determining an error in the brightness adjusting model. determining, by mobile User Equipment, UE, comprising a display and a light sensor, a first brightness value and a second brightness value, the first brightness value being acquired by the light sensor in a display state of the display during a display time window, the second brightness value being acquired by the light sensor in an off state of the display during an off time window, wherein the display is off during the off time window; determining a first drop depth value according to the first brightness value and the second brightness value; and acquiring a second ambient brightness value by adjusting a first ambient brightness value detected by the light sensor based on a brightness adjusting model acquired under predetermined ambient light and the first drop depth value, characterized in that the brightness adjusting model is acquired under the predetermined ambient light by: determining, under the predetermined ambient light, a third brightness value and a fourth brightness value, the third brightness value being acquired by the light sensor in the display state of the display during the display time window, the fourth brightness value being acquired by the light sensor in the off state of the display during the off time window; determining a second drop depth value according to the third brightness value and the fourth brightness value; and determining the brightness adjusting model for adjusting the first ambient brightness value by performing values fitting according to the second drop depth value and a third ambient brightness value under the predetermined ambient light, wherein the third ambient brightness value is determined according to known brightness of the predetermined ambient light, and is adapted to determining an error in the brightness adjusting model. determining, under the predetermined ambient light, a third brightness value and a fourth brightness value, the third brightness value being acquired by the light sensor in the display state of the display during the display time window, the fourth brightness value being acquired by the light sensor in the off state of the display during the off time window; determining a second drop depth value according to the third brightness value and the fourth brightness value; and determining the brightness adjusting model for adjusting the first ambient brightness value by performing values fitting according to the second drop depth value and a third ambient brightness value under the predetermined ambient light, wherein the third ambient brightness value is determined according to known brightness of the predetermined ambient light, and is adapted to determining an error in the brightness adjusting model.