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: May 9, 2007 /s/ J. Daniel MohrName:
J. Daniel MohrTitle:
Treasurer and Chief Financial Officer 29