  In this paper, we investigated the thermodynamic properties of strange quark
matter using Nambu-Jona-Lasinio (NJL) model at finite temperatures where we
considered the dynamical mass as the effective interaction between quarks.
  By considering the pressure of strange quark matter (SQM) at finite
temperatures, we showed that the equation of state of this system gets stiffer
by increasing temperature. In addition, we investigated the energy conditions
and stability of the equation of state and showed that the equation of state of
SQM satisfy the conditions of stability. Finally, we computed the structure
properties of hot strange quark stars (SQS) including the gravitational mass,
radius, Schwarzschild radius, average density, compactness and gravitational
redshift. Our calculations showed that in this model, the maximum mass and
radius of SQS increase by increasing temperature. Furthermore it was shown that
the average density of SQS is greater than the normal nuclear density, and it
is an increasing function of temperature. We also discussed the temperature
dependence of the maximum gravitational mass calculated from different methods.
