We have been monitoring Supernova (SN) 1987A with Chandra X-Ray Observatory since 1999. We present a review of previous results from our Chandra observations, and some preliminary results from new Chandra data obtained in 2006 and 2007. High resolution imaging and spectroscopic studies of SN 1987A with Chandra reveal that X-ray emission of SN 1987A originates from the hot gas heated by interaction of the blast wave with the ring-like dense circumstellar medium (CSM) that was produced by the massive progenitor's equatorial stellar winds before the SN explosion. The blast wave is now sweeping through dense CSM all around the inner ring, and thus SN 1987A is rapidly brightening in soft X-rays. At the age of 20 yr (as of 2007 January), X-ray luminosity of SN 1987A is Lx∼2.4×1036ergss-1 in the 0.5-10 keV band. X-ray emission is described by two-component plane shock model with electron temperatures of kT∼0.3 and 2 keV. As the shock front interacts with dense CSM all around the inner ring, the X-ray remnant is now expanding at a much slower rate of v∼1400kms-1 than it was until 2004 (v∼6000kms-1).