  We simulate light curves of the helium strong chemically peculiar star HD
37776 assuming that the observed periodic light variations originate as a
result of inhomogeneous horizontal distribution of chemical elements on the
surface of a rotating star. We show that chemical peculiarity influences the
monochromatic radiative flux, mainly due to bound-free processes. Using the
model of the distribution of silicon and helium on HD 37776 surface, derived
from spectroscopy, we calculate a photometric map of the surface and
consequently the uvby light curves of this star. Basically, the predicted light
curves agree in shape and amplitude with the observed ones. We conclude that
the basic properties of variability of this helium strong chemically peculiar
star can be understood in terms of the model of spots with peculiar chemical
composition.
