The (110) crystal surface of Si was bombarded by slow highly charged ions (Pbq+,Arq+) and the secondary particle emission was measured for different incident angles. Comparing the relationship between the sputtering yield and the incident angle, channeling effect was suggested. The channeling effect in interaction of highly charged ions with Si causes the sputtering yield to depend strongly on kinetic energy. Highly charged ions can enhance sputtering yield at smaller incident angles. At incident angles from 40° to 50°, the higher the potential energy of highly charged ion, the greater the sputtering yield.