@elanchezhiyan,

Based on the screenshot that you have shared, it seems like you have either set browser zoom or the scale option under display settings to 125%. In such cases, chart also gets zoomed as per your settings & exports at that particular resolution. Exporting at 100% browser & display scale settings seem to export chart at defined width & height.

However, if you like to keep browser / display scale settings at 125%, you will have to set width & height to 960×1440, so that you can export image at 1200×1800 pixels (125% of 960×1440 pixels).

—
Vishwas R
Team CanvasJS