labelFontFamily: String

Sets the font-family of stripLine’s label. If the first font is not found in the system from the specified font-family list, it tries to use the next font in the list.

Default: “Trebuchet MS, Helvetica, sans-serif”
Example: “Arial, Trebuchet MS, Tahoma, sans-serif”

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
axisY:{
    stripLines: [{
        .
        labelFontFamily: "Arial, Trebuchet MS, Tahoma, sans-serif",
        .
    }]
},
 .
 .
});
chart.render();