  In this paper, we propose a key idea and innovation on the Collatz problem.
Let an odd Collatz's Sequence be \[
S_{c}(m,t)=\{n_{0}(m,t),n_{1}(m,t),n_{2}(m,t),\ldots,n_{m}(m,t),n_{m+1}(m,t)\}
\] produced by a function $n_{i+1}(m,t)=(3n_{i}(m,t)+1)/2$ and ended by an even
number $n_{m+1}(m,t)$ where \[ n_{i}(m,t)=2^{m+1-i}\times3^{i}t-1\texttt{ for
}i=0,1,2,\ldots,m+1 \] and the positive integer $t$ is odd and not divisible by
$3$. Then in two ways we prove that each Collatz's Sequence always returns to
1, i.e., the Collatz problem is solved.
