White House staff chief Hamilton Jordon, flushed by success in his back-stage handling of the Panama Canal treaty, has decided to try his hand on another major congressional trouble spot - the administration's new tax reduction and "tax reform" package.

As he did in the campaign to ratify the canal treaty, Jordon has dispatched staff members to arrange a series of "constituent" meetings in which the White House will bring in out-of-town business and consumer groups to try to sell them on the president's proposal.

The idea is to build grass-roots support for the tax package in hopes that voters then will pressure their senators and representatives to back the Carter plan. The tax package is considered to be in trouble in the House and the Senate.

Jordon insisted in an interview, that the move was not designed to under-cut strategy-setting authority of Treasury Secretary W. Michael Blumenthal, who has been managing the tax package for the administration.

He also denied emphatically that the White House is unhappy with the secretary's handling of the tax package. He said Blumenthal will continue to be in charge of the administration's efforts on behalf of the legislation, and will be "the focal point" of the meetings with out-of-towners.

Jordon's decision to become involved in the tax bill's struggle through Congress was not applauded in all quarters. One administration official noted that pressure for changes in tax legislation most often is exerted by lobbyists in Washington, not voters at home.