Why total energy of a particle that moves along a circular path is always negative?

I don't understand what you are getting at. For a particle in motion its kinetic energy is always positive, since KE = \frac 1 2 m v^2 always yields a positive number. Perhaps you're thinking of gravitational potential energy, which mathematically is negative? For a body in orbit the sum of PE + KE does indeed work out to be a negative number - this quantity is known as "orbital energy" and is conserved.