The glass fibre reinforced plastic(GFRP) gantry in the earth electrode of Jingmen converter station apply GFRP composite materials to gantry of switchyard first in our country. To understand laoding characters of GFRP gantry, and considering joint connection rationality. GFRP gantry is designed to perform mechanical property under preliminary load，design load，over loading ,and measure corresponding gantry displacements。Test results show that it is practicality、rationalty and safety to apply GFRP composite materials to gantry，and through optimizing cross-section size and length of GFRP pipe，which weight is reduce 33% than steel gantry。Test results offer the basis of theory and practice for the extended application of GFRP gantry.