  The effect of the random quantum transverse field $\Omega$ on the tricritical
behavior of the spin-1 Blume- Emery- Griffiths (BEG) model is studied using
effective field theory. It is found, that the tricritical behavior depends on
both the biquadratic interaction $K$, single- ion anisotropy $\Delta$, and the
concentration $p$ of the disorder of $\Omega$. Indeed, there exist a special
value $p_{1}$ of the probability $p$ below which the tricritical behavior
disappears.
