Two bacteriophages of Pseudomonas aeruginosa Holloway strain 1 were isolated from sewage, named L1 and S2 respectively. Electron microscopic study revealed that both L1 and S2 had a tadpole-like structure. Phage L1 possessed an elliptical head of 89 × 67 nm, a tail of 150 × 5 nm and a knob structure at the tip. S2 had a polygonal head of 133 × 117 nm, with a tail of 133 × 25 nm in dimension; neck, tail sheath and baseplate also could be seen. Both phages contained double-stranded DNA.Using the method of assaying free phages, the average adsorption rate constant for L1 and S2 were 4.11 × 10^(-10) and 5,54 × 10^(-9) ml/min respectively. Other physiological properties, host range, thermal inactivation, UV inactivation, pH stability and chloroform sensitivity, were also determined.