Administrative Procedure Act Amendments of 1981 - Amends the Administrative Procedure Act to require the general notice of a proposed rulemaking to include certain information about the factual data on which the rule is based.

Requires each agency to provide the public with an opportunity: (1) to present oral arguments concerning a proposed rule after publication of such general notice; and (2) to comment on any factual data which is developed during the rulemaking and which is likely to affect the final rule. Requires an agency's statement, incorporated in the final rule, to include agency responses to significant public comments.

Directs each agency to establish a public file on each rulemaking proceeding, containing any notices, written data, written comments, and any other matter the agency is required to prepare for rulemaking.

Creates a new procedure for administrative proceedings required by statute. Establishes an "expedited hearing procedure" for any proceeding predominantly concerned with general policy issues, including ratemaking, rulemaking and initial licensing proceedings. Requires formal hearings for proceedings concerning factual questions which require trial-type procedures, including proceedings to assess a civil penalty or fine, or to determine a claim for certain individual benefits.

Directs the presiding employee at an expedited proceeding to conduct a hearing to provide an opportunity for parties to submit written arguments and responses and, at the request of any party, oral arguments. Requires such employee to designate a disputed question for resolution in a formal hearing upon determining that there is a substantial dispute of fact requiring the introduction of reliable evidence at a formal hearing, and that the agency decision is dependent on the resolution of such question.

Authorizes an agency to require the entire record of an expedited hearing to be certified to the agency for decision with or without the presiding employee's recommended decision, but with such employee's findings concerning any disputed question.

Authorizes each agency to establish employee boards to review the decisions of presiding employees of expedited and formal hearings.

Directs a court reviewing an agency action to: (1) set aside any agency rule found to lack substantial support in the rulemaking file; (2) determine the authority or jurisdiction of the agency on the basis of the language of the authorizing statute or other evidence of legislative intent; and (3) accord no presumption in favor of or against agency action.