A variationaI calcenlation of the energy of the 2s^{2 1}S state of helium has been carried out with the use of a waVe function of the Hylleraasian type. The wave function is Ψ=e^{-0.2278 s}1-0.17079 s-0.063155 u-03013869 t²+ 0.01004 u²+0.0064785 s² where s,t,u are in units of 4 times tho first Bohr radius of hydrogen. The energy is E(2s^{2 1}S)=-1.5412 Rh,compared with the value -1.4400 Rh obtained by the method of seIf-consistent field.