A method for implementing geo-fencing, comprising: when it is detected that a geo-fence is set, determining, by a mobile device, a first coordinate x1 representing the geo-fence in a first coordinate system A, wherein the first coordinate system A is a coordinate system used by the geo-fence; converting, by the mobile device, the first coordinate x1 into a second coordinate x representing the geo-fence in a second coordinate system B, wherein the second coordinate system B is a coordinate system that is set to implement geo-fencing and that is used by a positioning technology, and the first coordinate system A is different from the second coordinate system B; comparing, by the mobile device, a coordinate of a positioning result of the mobile device determined by using the positioning technology with the second coordinate x representing the geo-fence; and when a relationship between the coordinate of the positioning result and the second coordinate x representing the geo-fence satisfies a trigger condition, triggering, by the mobile device, a preset event, characterized in that the converting the first coordinate x1 into the second coordinate x representing the geo-fence in the second coordinate system B is performed by using an iterative offset estimation algorithm comprising: a) calculating an offset value d1=x2-x1 between the first coordinate x1 in the second coordinate system B and a coordinate x2 obtained by transforming x1 from the second coordinate system B to the first coordinate system A using a pre-stored B-A transformation model; b) estimating a value x' for x as x'=x1-d1; and c) branching back to step a) with x' in the place of x1, until the absolute value of d1 is less than a preset value. when it is detected that a geo-fence is set, determining, by a mobile device, a first coordinate x1 representing the geo-fence in a first coordinate system A, wherein the first coordinate system A is a coordinate system used by the geo-fence; converting, by the mobile device, the first coordinate x1 into a second coordinate x representing the geo-fence in a second coordinate system B, wherein the second coordinate system B is a coordinate system that is set to implement geo-fencing and that is used by a positioning technology, and the first coordinate system A is different from the second coordinate system B; comparing, by the mobile device, a coordinate of a positioning result of the mobile device determined by using the positioning technology with the second coordinate x representing the geo-fence; and when a relationship between the coordinate of the positioning result and the second coordinate x representing the geo-fence satisfies a trigger condition, triggering, by the mobile device, a preset event, characterized in that the converting the first coordinate x1 into the second coordinate x representing the geo-fence in the second coordinate system B is performed by using an iterative offset estimation algorithm comprising: a) calculating an offset value d1=x2-x1 between the first coordinate x1 in the second coordinate system B and a coordinate x2 obtained by transforming x1 from the second coordinate system B to the first coordinate system A using a pre-stored B-A transformation model; b) estimating a value x' for x as x'=x1-d1; and c) branching back to step a) with x' in the place of x1, until the absolute value of d1 is less than a preset value. a) calculating an offset value d1=x2-x1 between the first coordinate x1 in the second coordinate system B and a coordinate x2 obtained by transforming x1 from the second coordinate system B to the first coordinate system A using a pre-stored B-A transformation model; b) estimating a value x' for x as x'=x1-d1; and c) branching back to step a) with x' in the place of x1, until the absolute value of d1 is less than a preset value.