Thakur Prasad Mainali has created a number of environmental sculptures. Since they are outdoor sculptures, they enhance the setting and create an aesthetic sense of the space. Nationalism is the dominant subject matter of his sculptures. Various ethnic groups and nationalities get space in his works. He gives the sense of unity in diversity. Customs and culture of diverse communities are articulated in aesthetic form.
The themes of development and nation building are dealt with outmost details. The issues of national importance like agriculture, irrigation, health, education, transportation, law, peace and security are stressed in his environmental sculptures. The works depict the artist’s inner belief that for the substantial achievement the multiple development sectors should have equal attention. Agriculture and irrigation are the life line of the people and the nation. He seems to say education is the light of the life that leads toward success. The healthy citizens are the ones on which the nation stands. The works suggest that rule of law, peace and security facilitate the creation and construction. The national flag is recurrent image in his works which signifies the national unity. The inclusion of culture and spirituality imply the necessity of inner peace and tranquility.
Another significant dimension of his sculptures is the presentation of union of science and spirituality. The symbolic images of lotus are associated with mystical and spiritual concepts like prakriti, the female principle, the mother and the creator. At the same time, they are linked to physical construction and the underlined energy within our natural heritage like water resources, forest and snow-clad Himalaya. Similarly the icon of Shivalinga symbolizes the male principle, purusa or the individual sadhaka. The union of Shiva and Shakti, prakriti and purusa creates the cosmic harmony. The artist seems to suggest that despite the individual existence of various things, ultimately they are one, the absolute being. One image melts into other, the male figure melts into female figure, science merges with spirituality. The age old cultural beliefs, icons and symbols are recycled with new significance exploiting modern techniques.
The other images of natural heritage are mountains, valley and rivers. Buddhist and Hindu architecture merge with the images of nature. The presentation of stupa and pagoda architecture implies religio-cultural harmony and coherence.
Nevertheless, the artist does not present the images of external world in referential mode. The shapes and the expressions are altered to express the inner feeling. Sometimes, the geometric shapes like triangle, square and circle are employed to construct the monumental sculptures. Some sculptures resemble to the microcosm of reconstructed architecture. He uses multiple medium like metal, stone and clay to mold his creations.