This　work　studied　the　impact　of　path-loss　exponents　on　link　interference　and　network　capacity　in　802.11b　Wi-Fi　networks,　considering　multiple　bit　rates　selection,　which　is　useful　for　better　understanding　of　path　loss　impact　and　system　design.　We　made　the　following　observations.　First,　path　loss　exponents　have　two-side　effects　on　the　anti-interference　ability　(characterized　by　interference　distance　factor　f(i))　of　a　link,　depending　on　low　or　high　bit　rates:　fi　decreases　(or　increases)　with　larger　alpha　for　the　bit　rates　of　5.5　&　11Mbps　(or　1　&　2Mbps).　Second,　we　calculate　single-channel　capacity　in　cellular　topologies　which　depends　on　cluster　size,　path-loss　exponents　and　the　resulted　maximally　supported　bit　rate.　We　find　that　cell　capacity　increases　with　increasing　path-loss　exponent　for　the　same　cluster　size.　When　the　path-loss　exponent　is　large　enough　(4　or　5),　even　small　cluster　size　can　support　the　bit　rate　of　11Mbps　and　achieve　the　optimal　capacity.