Exhibit 31.2 CERTIFICATION OF THE CHIEF FINANCIAL OFFICER
Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002 I, J. Daniel
Mohr, hereby certify that: 1. I have
reviewed this quarterly report on Form 10-Q of Alliance Financial Corporation; 2. Based on my
knowledge, this quarterly report does not contain any untrue statement of a
material fact or omit to state a material fact necessary to make the statements
made, in light of the circumstances under which such statements were made, not
misleading with respect to the period covered by this quarterly report; 3. Based on my
knowledge, the financial statements, and other financial information included
in this quarterly report, fairly present in all material respects the financial
condition, results of operations and cash flows of the registrant as of, and
for, the periods presented in this quarterly report; 4. The
registrants other certifying officer and I are responsible for establishing
and maintaining disclosure controls and procedures (as defined in Exchange Act
Rules 13a-15(e) and 15d-15(e) ) and internal control over financial reporting
(as defined in Exchange Act Rules 13a-15(f) and 15d-15(f) ) for the registrant
and we have: a) designed
  such disclosure controls and procedures, or caused such disclosure controls
  and procedures to be designed under our supervision, to ensure that material
  information relating to the registrant, including its consolidated
  subsidiaries, is made known to us by others within those entities,
  particularly during the period in which this quarterly report is being
  prepared;b) designed
  such internal control over financial reporting, or caused such internal
  control over financial reporting to be designed under our supervision, to
  provide reasonable assurance regarding the reliability of financial reporting
  and the preparation of financial statements for external purposes in
  accordance with generally accepted accounting principles;c) evaluated
  the effectiveness of the registrants disclosure controls and procedures and
  presented in this report our conclusions about the effectiveness of the
  disclosure controls and procedures, as of the end of the period covered by
  this quarterly report based on such evaluation; andd) disclosed
  in this quarterly report any change in the registrants internal control over
  financial reporting that occurred during registrants most recent fiscal
  quarter that has materially affected, or is reasonably likely to materially
  affect, the registrants internal control over financial reporting; 5. The
registrants other certifying officer and I have disclosed, based on our most
recent evaluation of internal control over financial reporting, to the
registrants auditors and the audit committee of registrants board of
directors: a) all
  significant deficiencies and material weakness in the design or operation of
  internal control over financial reporting which are reasonably likely to
  adversely affect the registrants ability to record, process, summarize and
  report financial information; andb) any
  fraud, whether or not material, that involves management or other employees
  who have a significant role in the registrants internal control over
  financial reporting. Dated: November
8, 2006 /s/ J.
  Daniel MohrName: J.
  Daniel MohrTitle:
  Treasurer and Chief Financial Officer 34