A method for line width measurement, comprising: providing a substrate, wherein a raised line pattern is formed on a surface of the substrate, and the line pattern has a width; forming a first measurement structure and a second measurement structure on opposite sidewalls of the line pattern in the width direction of the line pattern; removing the line pattern; and measuring the spacing between the first measurement structure and the second measurement structure, and obtaining the width of the line pattern by subtracting a predetermined offset from the spacing. The present invention facilitates to reduce the uncertainty associated with the measuring process and to improve the measurement precision.