When the two end groups of a linear polymer chain are absorbed on a solid surface,the polymer chain forms the “loop” conformation.Investigation has been made on the conformational statistics of a model loop chain by the normal landom walk (NRW) on a lattice confined in the half-infinite space.Based on the conformational distribution function of the NRW model tail chain,it is easy to deduce an analytical formula expressing the conforma-tional number of the model loop chain.It was found that the ratio of the conformational number of the model loop chain to that of the free chain varies with the power function N-2/3 when the chain length N→∞ The same result was obtained by means of the recursion equation.The ratio of the mean square end-to-end distance h2 for the model loop chain to its mean square bond length I2 is 2N/3 Compared with the free chain with the same length N,the mean square end-to-end distance of the model loop chain contracts to a certain extent.The basic relationships deduced were support When the two end groups of a linear polymer chain are absorbed on a solid surface, the polymer chain forms the “loop” conformation.Investigation has been made on the conformational statistics of a model loop chain by the normal land walk (NRW) on a lattice confined in the half-infinite space. Based on the conformational distribution function of the NRW model tail chain, it is easy to deduce an analytical formula expressing the conforma- tional number of the model loop chain. It was found that the ratio of the conformational number of the model loop chain to that of the free chain varies with the power function N-2/3 when the chain length N → ∞ The same result was obtained by means of the recursion equation. The ratio of the mean square end-to-end distance h2 for the model loop chain to its mean square bond length I2 is 2N / 3 Compared with the free chain with the same length N, the mean square end-to-end distance of the model loop chain contracts to a certain extent.The basic relationship s deduced were support