To find out a more effective strengthening method for timber column with decay root, CFRP (Carbon Fibre Reinforced Plastic) sheet was employed to replace iron band in coating reinforcement technique. Six specimens were manufactured built, some of which had decay roots and strengthened by CFRP sheets using coating technique. Axial compression experiments were carried out to investigate the response of these six columns. The load-displacement relationships, load-strain relationships, ultimate compressive strength and ductility of the specimens were obtained to evaluate the strengthening effects. The influence of layer numbers of CFRP sheets was also discussed. The results showed that the ultimate compression strength and ductility of the strengthened columns were recovered to about 81.4% to 92.4% and 87.3% to 95.8% of those of the intact column, respectively. The peak compressive strain of the strengthened columns was also improved in both horizontal and vertical directions. The column strengthened by 3 layers of CFRP sheets exhibited better compressive performances than those of other strengthened columns, but still lower than that of the intact one.