Himalayan state Sikkim is a land of diversification. Diversified culture, tradition and religion is remarkable feature of this Himalayan state Sikkim. Lepchas are the earliest inhabitant of the Sikkim belongs to bodo section and considered as scheduled tribe of the state and known for their rich tradition culture and language. Beside Sikkim, they are also concentrated in Darjeeling, Kalimpong, Nepal and Bhutan. They have a legend, which says that they originated from Mayel Lyang a mythical land at the foothills of mount Kanchendzonga in Sikkim itselt. However their socio-cultural and economic conditions have been changing in recent years with the improvement in accessibility to modern technology and infrastructure services such as market, health, education, road etc. This paper is an attempt to delineate the ecology, economy and religious dimensions of the Lepcha of Sikkim Himalaya. This paper also tries to discuss the tradition and culture of the Lepcha which still continues and the changes taken place . This paper is based on field work conducted at village Ranka located in Gangtok subdivision of East district of Sikkim, India . This paper is purely qualitative study in nature. Primary data have been collected using Interview, Observation, Case Study, and Questionnaire techniques. Secondary data have also been incorporated as baseline data. References- Gorer, G; 1984 : The Lepchas of Sikkim, Gyan Publishing House, New Delhi Chattopadhyay,T;2013: Lepchas and their heritage, B.R.Publishing corp, Delhi Chakraborty, S; 2021: Lepcha Life and Culture, B.R. Publishing Corp, Delhi Chaudhury, S.K et.al. ; 2020: The Cultural Heritage of Sikkim, Routledge Vidyarthi, L.P. ; 1963: The Maler, Bookland pvt. ltd., Calcutta Das, A.K.; 1978: The Lepchas of West Bengal, Editions Indian, Calcutta Subba, T.B et.al.; June 1985: 'The Lepchas:From Legends to the Present day', published in " Religion and Society" Vol. XXXH, No. 2,