If you are referring to the common factors:
Factorize both numbers:
48 = 2*2*2*2*3
120 = 2*2*2*3*5
Common factors: 1, 2, 3, 4, 6, 8, 12, 24
If you are referring to factors in general:
48: 1, 2, 3, 4, 6, 8, 12, 16, 24, 48
120: 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120