This research was performed on the diversity of microorganisms in some hot springs located in Chiang Rai Province. This research aimed to 1) explore and classify microorganisms in Pong Phrabat hot springs, Muang district and Pong Pu Fueang hot spring, Mae Suai district in Chiang Rai Province. It is classified as an isolate of bacterial, fungi, yeast, actinomycetes, cyanobacterial and protozoa, and 2) to calculate the index of microbial diversity. This research was carried out by samples of microorganisms from 2 hot springs in Chiang Rai province were collected from April to June 2015 at a depth of 30 centimeters from the surface. The samples were taken in laboratory and classified as microbes. Using morphology and analysis by Dichotomous key. The results in Pong Phrabat hot springs and Pong Pu Fueang hot spring. Temperature water samples range of 35 to 52 degrees Celsius that pH about neutral (pH 7.0 - 9.0) which was suitable for growth of microbes. In Pong Phrabat hot springs, we obtained 4 types with different volume. The dominant that were found actinomycetes, 13 isolates, followed by fungi, yeast and protozoa, were 8, 3 and 3 isolates, respectively. This Shannon-Wiener Diversity Index was found to be the diversity index were actinomycetes, protozoa, yeast and fungi, were 2.44, 1.04, 0.98 and 0.85 respectively. And Pong Pu Fueang hot spring, we obtained 6 types with different volume. The dominant that were found actinomycetes, 21 isolates, followed by fungi, yeast, protozoa, bacterial and cyanobacterial, were 12, 4, 4, 1 and 1 isolates, respectively. The diversity index were actinomycetes, fungi, yeast, protozoa, bacterial and cyanobacterial. Were 3.01, 2.45, 1.30, 1.25, 0.00 and 0.00.